“Cutting effect” of organoclay platelets in compatibilizing immiscible polypropylene/polystyrene blends
Yan ZHU, Hai-yun MA, Li-fang TONG, Zheng-ping FANG
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Institute of Polymer Composites, Zhejiang University, Hangzhou 310027, China; Department of Biochemical and Chemical Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China
Abstract In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mechanism, “cutting” to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special “knife-like structure” in the PS domain under the shear stress of the continuous PP phase during compounding. The “clay knife” can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.
